Structure for reducing a flow resistance of a body in a fluid

Abstract

The invention relates to a body ( 10 ) having at least one surface ( 12 ) over which a fluid ( 30 ) can flow, said surface having a global course that defines a main flow direction ( 14 ) over the surface ( 12 ) at least partially has a structure for reducing a flow resistance of the body ( 10 ), the structure having at least one recess ( 16.2 . . . 16.3 ) provided with a substantially circle-segment-shaped cross-section for inducing a fluid eddy ( 26.2 ) . . . 26.3 ). The body is characterized in that the structure has at least one lead-in section ( 18.2 . . . 18.3 ), which is angled from the main flow direction in the direction of the recess ( 16.2 . . . 16.3 ) and which is arranged upstream of the recess ( 16.2 . . . 16.3 ) in the main flow direction, for leading a fluid flow ( 24 ) into the recess ( 16.2 . . . 16.3 ). By means of the structure, a fluid eddy ( 26.2 . . . 26.3 ) can be induced within the recess ( 16.2 . . . 16.3 ) and can be localized substantially within the recess ( 16.2 . . . 16.3 ).

1 . Body having at least one surface over which a fluid can flow, said surface having a global course that defines a main flow direction over the surface,
 wherein the surface at least partially has a structure for reducing a flow resistance of the body, the structure having   at least one recess for inducing a fluid eddy and   at least one lead-in section angled with respect to the main flow direction towards the recess   which is arranged upstream of the recess in the main flow direction for leading a fluid flow into the recess,   
       characterized in that
 the recess is provided with a circle-segment-shaped cross-section and formed such that by a fluid flow led over the surface a fluid eddy is induced within the recess which recess is configured such that the fluid eddy substantially remains within the recess and creates air cushions across which continuing fluid flow is led. 
 
     
     
         2 . Body according to  claim 1 , wherein the recess extended transverse to the main flow direction is in particular groove-shaped. 
     
     
         3 . Body according to  claim 1 , wherein the structure has a plurality of recesses wherein the majority of the recesses are arranged one behind the other, particularly in the main flow direction. 
     
     
         4 . Body according to  claim 3 , wherein adjacent recesses, are spaced apart from each other by 1 to 6 times the diameter of the circle-segment-shaped cross-section, depending on the density, viscosity and temperature of the fluid. 
     
     
         5 . Body according to  claim 1 , wherein the lead-in section is configured in a straight line and/or curved, wherein the radius of curvature in particular measures 2 to 6 times the diameter (D) of the circle-segment-shaped cross-section, depending on density, viscosity and temperature of the fluid. 
     
     
         6 . Body according to  claim 1 , wherein the lead-in section is configured in such a manner that the inclination between the main flow direction and the tangent parallel to the main flow direction is greater at a first point of the lead-in section than at a second point which is situated upstream in the main flow direction with respect to the first point. 
     
     
         7 . Body according to  claim 1 , wherein the recess has a first edge situated upstream in the main flow direction between the lead-in section and the recess and a second edge situated downstream between the recess and a portion of the surface situated downstream, wherein the first edge is offset with respect to the second edge towards the inside of the body in order to induce the fluid eddy in the recess. 
     
     
         8 . Body according to  claim 7 , wherein the point of the recess situated furthest upstream is offset with respect to the first edge towards the inside of the body in order to localize the fluid eddy inside the recess. 
     
     
         9 . Body according to  claim 7 , wherein the second edge is offset with respect to the center spot (M) of the recess in the main flow direction by 0.1 to 0.6 times the radius of the circle-segment-shaped cross-section, 
     
     
         10 . Body according to  claim 7 , wherein the second edge has a protrusion against the main flow direction and angled towards the recess for leading the fluid eddy over to a subsequent recess. 
     
     
         11 . Body according to  claim 1 , wherein the circular-arc-segment of the cross-section of the recess measures between 181° and 315°, depending on the density, viscosity and temperature of the fluid,
 such that the recess is open over an angular range of between 179° and 45°, of its cross-section. 
 
     
     
         12 . Flow path having a body according to  claim 1 . 
     
     
         13 . Jet engine having a body according to  claim 1 . 
     
     
         14 . Lift device having a body according to  claim 1 . 
     
     
         15 . Film having a structure for reducing a flow resistance of a body over or around which a fluid flows in a main flow direction, and on whose surface the film can be applied, wherein the structure has
 at least one recess for inducing a fluid eddy and at least one lead-in section angled with respect to the main flow direction towards the recess which is arranged upstream of the recess in the main flow direction for leading a fluid flow into the recess, wherein   the recess is provided with a circle-segment-shaped cross-section and formed such that by a fluid flow led over the surface a fluid eddy is induced within the recess which recess is configured such that the fluid eddy substantially remains within the recess and creates air cushions across which continuing fluid flow is led.   
     
     
         16 . (canceled) 
     
     
         17 . Body according to  claim 7 , wherein the second edge is offset with respect to the center spot (M) of the recess in the main flow direction by 0.3 times the radius of the circle-segment-shaped cross-section. 
     
     
         18 . Body according to  claim 11 , wherein the circular-arc-segment of the cross-section of the recess measures between 260° and 290° such that the recess is open over an angular range of between 100° and 75° of its cross-section. 
     
     
         19 . Flow path according to  claim 12  wherein said flow path is a supersonic flow path.